Our studies are centered on the elucidation of function to non-histones in chromatin. We have been able to amplify the types of non-histone chromosomal proteins which may be associated to DNA and assign a chromatin to a specific organ on the basis of its NHCP complements. Principally, non-histone chromosomal proteins (NHCP) were isolated from rabbit liver chromatin in 5M urea, and in 5M urea with stepwise increase in NaCl molarity. Five different fractions were obtained, including 5M urea extracted chromatin, 5M urea-0.5M NaCl, 5M urea-05 to 1.OM NaCl, 5M urea-1.0 to 1.5M NaCl, and 5M urea-1.5 to 2.OM NaCl. A total of 94 bands of different electrophoretic mobilities were found for non-histone chromosomal proteins isolated from rabbit liver. In addition, studies on the melting profiles of the DNA pellets obtained from the variously treated chromatin indicated that DNA of rho equals 1.688 g/cm3 may have tightly-bound non-histones associated to it (i.e., non-histones which are dissociated between 1.5 and 2.OM NaCl in 5M urea). This fraction contained specific non-histones relative to the other fractions which were obtained at the lower NaCl molarity and which lacked histones (except for histone III). Additional experiments are now being carried out to possibly relate some regulatory function to NHCP.